Seeds of Life in Space (SOLIS). III. Zooming Into the Methanol Peak of the Prestellar Core L1544

Anna Punanova (1, 2) , Paola Caselli (2) , Siyi Feng (2) , Ana Chacon-Tanarro (2) , Cecilia Ceccarelli (3) , Roberto Neri , Francesco Fontani (4) , Izaskun Jimenez-Serra (5) , Charlotte Vastel (6) , Luca Bizzocchi (2) , Andy Pon (7) , Anton I. Vasyunin (1) , Silvia Spezzano (2) , Pierre Hily-Blant (3) , Leonardo Testi (8) , Serena Viti , Satoshi Yamamoto (9) , Felipe Alves (2) , Rafael Bachiller , Nadia Balucani (10) , Eleonora Bianchi (4, 11) , Sandrine Bottinelli (6) , Emmanuel Caux (6) , Rumpa Choudhury , Claudio Codella (4) , Francois Dulieu (12) , Cecile Favre (4) , Jonathan Holdship , Ali Jaber Al-Edhari (3) , Claudine Kahane (3) , Jake Laas , Bertrand Lefloch (3) , Ana Lopez-Sepulcre (3) , Juan Ospina-Zamudio (3) , Yoko Oya (9) , Jaime E. Pineda , Linda Podio (4) , Davide Quenard (5) , Albert Rimola (13) , Nami Sakai (14) , Ian R. Sims (15) , Vianney Taquet (16) , Patrice Theulé (17) , Piero Ugliengo (18)

1 UrFU - Ural Federal University [Ekaterinburg]
2 MPE - Max Planck Institute for Extraterrestrial Physics
3 IPAG - Institut de Planétologie et d'Astrophysique de Grenoble
4 OAB - INAF - Osservatorio Astronomico di Brera
5 QMUL - Queen Mary University of London
6 IRAP - Institut de recherche en astrophysique et planétologie
7 UWO - University of Western Ontario
8 OAA - INAF - Osservatorio Astrofisico di Arcetri
9 UEC - University of Electro-Communications [Tokyo]
10 UNIPG - Università degli Studi di Perugia = University of Perugia
11 UniFI - Università degli Studi di Firenze = University of Florence = Université de Florence
12 LERMA (UMR_8112) - Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique
13 UAB - Universitat Autònoma de Barcelona = Autonomous University of Barcelona = Universidad Autónoma de Barcelona
14 RIKEN - RIKEN - Institute of Physical and Chemical Research [Japon]
15 IPR - Institut de Physique de Rennes
16 Universiteit Leiden = Leiden University
17 PIIM - Physique des interactions ioniques et moléculaires
18 UNITO - Università degli studi di Torino = University of Turin

Toward the prestellar core L1544, the methanol (CH3OH) emission forms an asymmetric ring around the core center, where CH3OH is mostly in solid form, with a clear peak at 4000 au to the northeast of the dust continuum peak. As part of the NOEMA Large Project SOLIS (Seeds of Life in Space), the CH3OH peak has been spatially resolved to study its kinematics and physical structure and to investigate the cause behind the local enhancement. We find that methanol emission is distributed in a ridge parallel to the main axis of the dense core. The centroid velocity increases by about 0.2 km s(-1) and the velocity dispersion increases from subsonic to transonic toward the central zone of the core, where the velocity field also shows complex structure. This could be an indication of gentle accretion of material onto the core or the interaction of two filaments, producing a slow shock. We measure the rotational temperature and show that methanol is in local thermodynamic equilibrium (LTE) only close to the dust peak, where it is significantly depleted. The CH3OH column density, N-tot(CH3OH), profile has been derived with non-LTE radiative transfer modeling and compared with chemical models of a static core. The measured N (tot)(CH3OH) profile is consistent with model predictions, but the total column densities are one order of magnitude lower than those predicted by models, suggesting that the efficiency of reactive desorption or atomic hydrogen tunneling adopted in the model may be overestimated; or that an evolutionary model is needed to better reproduce methanol abundance.

Mots clés: Molecular physics; stars formation; ISM molecules; ISM individual objects (L1544); ISM clouds; ISM kinematics and dynamics; radio lines ISM

Domaines: Physique [physics]

Anna Punanova, Paola Caselli, Siyi Feng, Ana Chacon-Tanarro, Cecilia Ceccarelli, et al.. Seeds of Life in Space (SOLIS). III. Zooming Into the Methanol Peak of the Prestellar Core L1544. The Astrophysical Journal, 2018, 855 (2), pp.112. ⟨10.3847/1538-4357/aaad09⟩. ⟨hal-01771074⟩